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NOTE: Starting in MIG v1.5, available with ISE 14.1, this step can be skipped. Go directly to Step 2.

2. Modify the following top level parameters in the "example_design/rtl/example_design.v" and "user_design/rtl/core_name.v" modules:

RTT_NOM = "DISABLED"RTT_WR = "60"USE_ODT_PORT = "0"

As per the Jedec standard, Dynamic ODT cannot be used during Write Leveling.

For this reason, the 7 Series MIG PHY turns Dynamic ODT off and sets RTT_NOM to 40 ohm before Write Leveling.

After Write Leveling completes, the MR1 and MR2 mode registers are reprogrammed with the Dynamic ODT settings (RTT_NOM=Disabled and RTT_WR=60).

When running a simulation, you will see Dynamic ODT disabled settings during initialization, but then a second set of MR1/MR2 commands sent after Write Leveling completes showing the appropriate Dynamic ODT settings as follows: